Handle errors correctly

internal/storage/messages.go

@@ -593,7 +593,9 @@ func DeleteMessages(ids []string) error {
 		}
 	}
 
-	err = tx.Commit()
+	if err := tx.Commit(); err != nil {
+		return err
+	}
 
 	dbLastAction = time.Now()
 	addDeletedSize(int64(totalSize))

internal/storage/schemas.go

@@ -137,7 +137,9 @@ func dbApplySchemas() error {
 
 		buf := new(bytes.Buffer)
 
-		err = t1.Execute(buf, nil)
+		if err := t1.Execute(buf, nil); err != nil {
+			return err
+		}
 
 		if _, err := db.Exec(buf.String()); err != nil {
 			return err

server/pop3/pop3_test.go

@@ -67,7 +67,7 @@ func TestPOP3(t *testing.T) {
 		return
 	}
 
-	count, size, err = c.Stat()
+	count, _, err = c.Stat()
 	if err != nil {
 		t.Errorf(err.Error())
 		return